Among the 26 most populous countries, Brazil has the highest levels of religious freedom, higher, in fact, than the United States, where government restrictions on religious freedom have been rising.

the Weekly Number

Brazil - the world's fifth most populous nation - not only out performs other countries of is size, the Brazilian government has the best record on religious freedom worldwide, placing virtually no measurable restrictions on religious freedom, scoring 0.2 out of a maximum of 10.0 on the Government Restrictions on Religion index, recently published by the Pew Research Center.

Brazil is also one of only six countries among the 26 most populous where government restrictions on religion have decline since the Pew study began making these estimates. The others are the Philippines, the D.R. Congo, Mexico, Vietnam, and Burma (Myanmar).

Countries with the greatest increases in government restrictions on religion between 2007 and 2013 are:

Today, the world's seventh largest Christian population lives in China. By 2050 it could become the world's largest. This has been argued by sociologist Fenggang Yang of Purdue University.

Prof. Yang is one of the world’s leading experts on religion in China. He estimates that the Christian population in China grew at an average annual rate of 7% between 1950 and 2010. At this rate, he estimates that the Christian proportion of China’s population could grow from about 5% in 2010 to 67% in 2050.

While a new study by the Pew Research Center concludes that the religious future of China is uncertain due to data limitations, of which I've written extensively,* the Pew study offers three "sensitivity tests" looking at the effects of religious switching on the future size of the Chinese Christian population:

"As of 2010, China had an estimated 68 million Christians and 701 million unaffiliated people. Due primarily to differences in the age and sex composition of these initial populations, in the main projection scenario – which does not attempt to model religious switching – China’s Christian population is expected to grow slightly by 2050, to 71 million, while the unaffiliated population is expected to decline to 663 million."

"Under that main scenario, 5.4% of China’s population and 31.4% of the world’s total population will be Christian in 2050. If China’s Christian population were to decline to Japanese levels (2.4% of the country’s population) in 2050, it would reduce the Christian share of the global population to 30.9%. On the other hand, if China’s Christian population was to increase to the level projected for South Korea in 2050 (33.3% of the country’s population), it would raise the count of Christians in China to 437 million and the share of Christians in the world’s overall population to 35.3%."

"And if everyone who is currently unaffiliated in China were to convert to Christianity by 2050, China’s population would be 56.2% Christian (734 million Christians), raising the Christian share of the world’s population to 38.5% and lowering the unaffiliated share of the global population to 6.1%. Though that scenario may be unlikely, it offers a rough sense of how much difference religious switching in China maximally could have by 2050. Extremely rapid growth of Christianity in China could maintain or, conceivably, even increase Christianity’s current numerical advantage as the world’s largest religion, and it could significantly accelerate the projected decline by 2050 in the share of the global population that is religiously unaffiliated." (Pew Research)

* The reason that the religious future in China is so difficult to estimate is due to measurement difficulties ranging from reluctance of individuals to disclose religious affiliation to pollsters to the massive internal migration that has seen well over one hundred million people move from the countryside into cities since 1980. Much of this movement - considered the largest migration in human history - is difficult to track and count, including whether the Christians who moved from the countryside have stimulated Christian growth in cities or have lost touch with their roots. Thus, there are no reliable sources to precisely measure patterns of religious conversion in China.

In a new study reported in Demographic Research, my colleagues and I offer new demographic estimates of the size of major religious groups projected to 2050.* (For my analysis of the economic and security implications of this, see links at bottom.)

From the introduction: "Social scientists have a long history of predicting the demise of religion. Auguste Comte, Emile Durkheim, Sigmund Freud, and Karl Marx envisioned the decline of organized religion and the rise of the religiously unaffiliated. More recently the idea that the unaffiliated population will increase has been promoted using mathematical models of social group competition (Abrams, Yaple et al. 2011) and assumptions that growing economic development will lead to evolution away from religion (Barber 2012). But these predictions did not take demography into account − specifically, that patterns in global population growth favor those who have religious affiliation (Norris and Inglehart 2004; Kaufmann 2010)."

"Our new demographic analysis finds that affiliated women have more children than unaffiliated women − nearly a full child more per woman, on average, worldwide. In addition, the global median age of affiliated women is six years younger than unaffiliated women, so they have more potential years of childbearing and living ahead. We project these demographic characteristics will result in a more religiously affiliated global population in coming decades. Although current patterns of religious switching favor the unaffiliated, they are insufficient at the global level to offset the demographic advantages of the affiliated."

Background: People who are religiously unaffiliated (including self-identifying atheists and agnostics, as well as those who say their religion is "nothing in particular") made up 16.4% of the world's population in 2010. Unaffiliated populations have been growing in North America and Europe, leading some to expect that this group will grow as a share of the world's population. However, such forecasts overlook the impact of demographic factors, such as fertility and the large, aging unaffiliated population in Asia.Objective: We project the future size of religiously affiliated and unaffiliated populations around the world.Methods: We use multistate cohort-component methods to project the size of religiously affiliated and unaffiliated populations. Projection inputs such as religious composition, differential fertility, and age structure data, as well as religious switching patterns, are based on the best available census and survey data for each country. This research is based on an analysis of more than 2,500 data sources.Results: Taking demographic factors into account, we project that the unaffiliated will make up 13.2% of the world’s population in 2050. The median age of religiously affiliated women is six years younger than unaffiliated women. The 2010-15 Total Fertility Rate for those with a religious affiliation is 2.59 children per woman, nearly a full child higher than the rate for the unaffiliated (1.65 children per woman).Conclusions: The religiously unaffiliated are projected to decline as a share of the world's population in the decades ahead because their net growth through religious switching will be more than offset by higher childbearing among the younger affiliated population.